(a) Field of the Invention
The present invention relates to a display device, more precisely a display device to improve the visibility and display quality.
(b) Description of the Related Art
A liquid crystal display (LCD) is one of the most widely used flat panel displays. An LCD includes two substrates on which electrodes are formed and a liquid crystal layer that is interposed there between. When a voltage is applied to the electrodes, the electric field is generated and the liquid crystal molecules are re-arranged. The polarizers and liquid crystal molecules control the amount of the transmittance of the light to display images.
In the vertical alignment mode (VA mode), when the voltage is not applied to the electrodes, the long axes of the liquid crystal molecules are vertically aligned to the substrate. The LCD of the VA mode has a high contrast ratio allowing for a wide viewing angle. To achieve a wide viewing angle in the VA mode, a protrusion or aperture is formed on the electrode.
To improve visibility, one pixel electrode is divided into two sub pixel electrodes displaying different gray levels. Many methods are used to display different gray levels in the sub pixel electrodes. One method is to apply the same voltage to two sub pixel electrodes and to share the charges between the two sub pixel electrodes. As a result, the voltage level of one sub pixel electrode is high and the voltage level of the other sub pixel electrode is low. In such a method, one pixel region is controlled by two gate lines. But on the last line, one gate line runs short so a voltage difference between the sub pixel electrodes does not arise. As a result, the pixel electrodes of the last line may be brighter than the pixel electrodes of other lines.